Coral reefs are spectacular ecosystems teeming with a fascinating array of marine life. Despite covering less than 0.2% of our oceans, reefs are home to 25% of the world’s marine fish species. This diverse community is being threatened by rapid change which includes elevated sea temperatures, increased acidity, destructive fishing and coastal development.
We have a number of tropical coral displays which include numerous reef building stony corals and a colourful collection of soft corals. Stony corals provide the solid framework of a coral reef by producing limestone skeletons. Unlike stony corals which form these rigid skeletons, soft corals are flexible and contain tiny structures called ‘sclerites’ that give them their support.
Soft corals are an important component of the reef ecosystem, providing habitats for fish, crabs, algae and an abundance of other sea creatures. Coral reefs are extremely important to people as they provide food, jobs and coastal protection amongst other resources.
The research we conducted allowed us to better understand the biology of corals. Using this information we can answer important questions which will help to better protect them in their natural environment.
- Investigating coral spawning of Table corals
- Investigating growth of Cauliflower corals
- Investigating settlement of Cauliflower corals
- Investigating growth of Carnation tree coral
Investigating coral spawning of Table corals
Table corals (Acropora species) are major reef building animals responsible for constructing immense calcium carbonate structures known as coral reefs. The main mode of reproduction is asexual in which a new organism grows from a fragment of the parent.
In sexual reproduction, male and female gametes are released into the water in a synchronized spawning event. Timing is critical! Corals rely on a number of cues, such as temperature, lunar and daily cycles, to ensure male and female gametes meet.
Spawning has been witnessed in aquariums but has occurred unexpectedly. As far as we know, Table corals in public aquariums have never been predictably sexually reproduced under human care. With advances in technology it has now become possible to replicate the key environmental conditions required to encourage spawning.
The study, run by the Horniman Museum and Gardens Aquarium in Forest Hill and the S.E.A. Aquarium at Resorts World Sentosa, aimed to reproduce captive corals simultaneously in South London and Singapore. The corals have been collected locally from Kusu and Raffles Lighthouse reefs off the coast of Singapore and are being kept in conditions mirroring those of their natural environment. The partnership also includes the SECORE foundation, which is providing scientific support and updates from the Singaporean reef.
Understanding how corals reproduce is critical to their survival. Currently researchers are limited to studying a single annual spawning event in the field. By combining the scientific knowledge of Singapore’s reefs, with husbandry expertise and development in technology, we hope to increase the chances of a successful spawning event under human care. Success of this project will allow researchers to further investigate the ability of broadcast corals to recover from such disturbances such as climate change.
Investigating growth of Cauliflower corals
Cauliflower corals (Pocillopora species) are tough, widespread hard corals which are found as solid dome shapes or branching formations with many variations. Cauliflower corals are commonly collected for trade. They are used as construction material to make lime, which in turn is used to make concrete. They can reproduce asexually and are thought to be fairly resilient to collection; however their trade remains internationally regulated to ensure they are not over-exploited.
Establishing coral reef habitats within aquariums requires good understanding on how these animals thrive in the wild. Over the course of many years, hard corals can grow and create massive reef structures. Many factors have been shown to affect the growth of corals. We are studying the effect of temperature and variation in food on the growth of Cauliflower corals. Our dedicated aquarist team is committed to providing the best husbandry care, whilst simultaneously learning more about these animals to ensure we advance current protocols.
Investigating settlement of Cauliflower corals
To reproduce, the Cauliflower coral will release free-swimming larvae called ‘planulae’ into the water column. The planulae will actively search their surroundings to find a suitable place to settle. If conditions are favorable they will settle down and once in place they cannot move. Therefore a poor choice of location can have a significant effect on their survival. The larvae can then grow, develop and form colonies that can reproduce again.
In partnership with the Nanyang Technological University (NTU), Singapore, we studied Cauliflower corals and factors that affect settlement of their larvae during reproduction. The controlled conditions we provided at S.E.A. Aquarium made it a perfect environment for studying this process.
What’s more, not only will the information help us to maintain our own coral reefs at the aquarium, it will help us to protect coral reefs in the wild. The Cauliflower coral is a hard coral that plays an important role in reef building and repair, especially here in Singapore waters.
Investigating growth of Carnation tree corals
The Carnation tree corals (Dendronephthya species) belong to a group known as the soft corals- typically flamboyant in colour they bend and sway with the ocean’s movement. Unlike stony corals which form rigid skeletons, these corals are soft and flexible and have tiny ‘spines’ that give them their structure.
Most soft corals house algae inside their tissues which produce oxygen for the corals and help them remove waste. Importantly, the algae supply the coral with sugars and amino acids meeting most of the coral’s needs. In return, the corals provide the algae with a protected environment and the resources they need for photosynthesis
Carnation tree corals however, do not host algae in their tissues and instead feed on tiny animals, plants and other types of organisms known collectively as plankton. Soft corals are known to be difficult to keep in aquariums, however with our experienced aquarist team and excellent on-site facilities we can create the appropriate environment and provide the best husbandry for these animals.
Carnation tree corals are known to require low light, intermittent water movement and an abundance of food. The aim of the project is to further explore the factors that affect the growth of these soft corals in order to make advances in husbandry protocols.